<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
        <title>window sizes</title>

        <script>
            function updateText(elem) {
                var size = window.innerWidth + "/" + window.innerHeight;
                document.getElementById(elem).textContent = size;
                console.log(elem + " window size: " + size);
            }

             document.addEventListener("DOMContentLoaded",  function() {
                 updateText("hidden");
                 console.log("loaded");
             });
        </script>
    </head>
    <body>
        <p>visible: <span id="visible">unknown</span></p>
        <p>hidden: <span id="hidden">unknown</span></p>
    </body>
</html>
